Vaporizing burner

ABSTRACT

A closed furnace vaporizing burner and a feed therefor suitable for adapting to a closed fireplace, transforming it into a liquid fuel fireplace. The invention comprises two distinct portions: The fuel feed comprising the inlet  1,  an air-liquid separator  2,  an injector tube  3  terminated by two downwardly bent small-diameter tubes  30,  a cooling tube  4,  a holding and protection tube  13,  two protective tubes  16  and  18  or a heat-recovery cooler  39,  and a support  10.  The combustion assembly comprises an air feed and hearth support box  20,  a fan  22,  a combustion pot  26,  a receptacle  27,  horizontal disks of grid, or expanded metal, or perforated sheet metal  31,  radial fins  36,  a transparent ceramic glass tube  38,  a reflecting screen  47,  and in a variant, air injection rings  41  and transparent ceramic glass tubes  42.

[0001] The present invention relates to a vaporizing burner and its feed, the burner being suitable for fitting to a closed fireplace enabling it to be transformed from a woodburning fireplace to a liquid fuel fireplace.

[0002] A closed woodburning fireplace presents constraints concerning the handling of fuel and cleaning the hearth which discourage continuous use.

[0003] The device of the invention makes it possible to remedy those drawbacks, e.g. for power in the range 2 kilowatts (kW) to 14 kW.

[0004] It comprises two distinct portions:

[0005] The first portion is the device for feeding fuel. This device comprises a conventional feed (mini-tank, filter, solenoid valves, constant level vessel), an air-liquid separator, and an inclined double-walled tube that penetrates into the fireplace via the rear wall of the hood and whose final end is terminated at a point vertically above the center of the burner by two downwardly bent tubes of small diameter that are spaced apart by a few millimeters.

[0006] The portion of the tube outside the fireplace includes a cross enabling it to be filled with distilled water via a flexible transparent tube for monitoring water level, and for continuously monitoring pressure, by means of a conventional pressure gauge; the assembly as a whole forming a sealed radiator for cooling the inner portion. The portion of the tube inside the fireplace is held by a larger-diameter tube terminated by a portion extending vertically downwards that protects the liquid fuel after it has left the feed tube. For maximum effectiveness, this tube can be surrounded by a tube of greater diameter, or in its vertical portion by an air-water heat-recovering cooler of appropriate shape. This tube can pivot inside its support about the feed tube so as to leave the hearth unencumbered, e.g. while burning wood.

[0007] It can also be used, during a period of using wood, to light a fire by impregnating the solid fuel with some liquid fuel.

[0008] The continuous slope of the double-walled tube makes it possible firstly for liquid fuel to flow under gravity inside the small-diameter inner tube, and secondly to cool said fuel by a heat-pipe effect produced by demineralized water in the outer tube surrounding the fuel. The water flows within the tube and cools the injector tube. The temperature of the injector tube thus remains within highly acceptable limits. A cold water pressure of about 0.5 bars is good on average.

[0009] This first portion is considered as being fixed relative to the fireplace.

[0010] The second portion which provides combustion is the assembly which is placed in the center of the hearth.

[0011] This assembly comprises two distinct portions.

[0012] The first is the box feeding the fresh air necessary for combustion.

[0013] This box is of a shape that is adapted to each type of fireplace so as to make the fireplace air inlet match the air inlet of the box.

[0014] The box contains a propeller type fan having a vertical axis which coincides with the liquid fall axis; this variable speed fan can be a low voltage fan.

[0015] The second portion is the hearth proper, which is placed vertically above the fan, on a circular stamped metal support standing on two rear adjustment screws situated at 120° from each other.

[0016] Its center has a vaporizing receptacle in the form of a “Mexican hat” placed thereon. It can be in one piece or in two. The conical portion having a small angle at the apex receives the drops of liquid fuel and prevents them from splashing into the burner. The receptacle is preferably made of ceramic glass and is easy to clean. It is centered by a circular piece having six rods, or by a stamping in the bottom of the burner.

[0017] Inside the burner, a plurality of horizontal layers of disks that are solid, or made of grids, or of expanded metal, or of perforated sheet metal, are separated from one another by tubular spacers and provide good combustion with a glowing embers effect.

[0018] A central tube prevents the drops of liquid fuel from coming into direct contact with the flames.

[0019] The simplest structure comprises the central wall with a bottom, all made of metal, placed on the outer wall of transparent ceramic glass. An intermediate piece provides support and centering.

[0020] The combustion pot can be a commercially available stamping, such as a pressure cooker.

[0021] The outer wall makes it possible to see the reddening of the pot and the combustion at various spots through the air injection holes of the pot.

[0022] A more sophisticated structure comprises two walls of transparent ceramic glass giving a full view of combustion.

[0023] Vertical fins placed radially between the two walls serve to eliminate the turbulence effect due to the fan, where this effect can lead to poor combustion. A metal sheet is spaced a few millimeters beneath the combustion pot and serves to protect the fan from the heat due to direct radiation emitted by the bottom of the pot.

[0024] A shape stamped out of sheet metal enhances air flow. Behind the hearth, a polished sheet metal portion in the form of a vertical axis circular arc reflects the light from the hearth in a forward direction.

[0025] Two thermocouples in the top of the hearth provide safety for the system, by acting on two normally-closed solenoid valves placed in series in the fuel circuit. A contactor enables the two valves to be opened when lighting the fire.

[0026] Gravity feed can be replaced by a system using a variable flow rate micropump. Under such circumstances, it is no longer necessary to have the air-liquid separator.

[0027] The entire burner and fuel feed assembly can be a self-contained heating system without it necessarily being installed in a fireplace.

[0028] Naturally, it is advisable to have a system for recovering heat from the flue gases, so as to ensure that the installation has proper efficiency. This can be an air-water heat-recovering cooler installed directly in the flames of the hearth, thus reducing the temperature of the fuel prior to combustion.

[0029] All of the elements should be made out of materials that withstand corrosion, for example:

[0030] accessories before the injector tube: copper;

[0031] injector tube and coolers: cooper, or better stainless steel;

[0032] accessories for holding the coolers: stainless steel;

[0033] box: aluminum alloy;

[0034] hearth components: refractory stainless steel or ceramic glass, stainless steel; and

[0035] reflecting screen: polished aluminum.

[0036] Modular construction makes it easy to exchange certain parts.

[0037] The elements inside the pot are merely placed inside the pot, and the pot is placed on the box without being fixed, so the hearth is very easy to handle for cleaning purposes.

[0038] Since the end of the fuel injector tube is situated at the top of the vertical protective tube, it is not reached by combustion products and thus remains clean for a very long time. Since this end is terminated by two downwardly bent tubes of small diameter, fuel flow takes place without dispersion whatever the flow rate used (within the limits set initially).

[0039] When starting, it is necessary to use a complementary fuel, such as methylated spirits, to preheat the burner.

[0040] Thereafter, it suffices to match the speed of rotation of the fan to the liquid fuel flow rate for best combustion (without smoke or significant flame).

[0041] The accompanying drawings illustrate the invention.

[0042]FIG. 1 is a general diagram of the installation.

[0043]FIG. 2 shows the fuel feed device.

[0044]FIG. 3 comprises a left half-section showing the burner and its accessories together with the metal inside wall and the outer wall of transparent ceramic glass, and a right half-section showing a variant with two walls of transparent ceramic glass.

[0045]FIG. 4 is a section through the air-water heat-recovery cooler (minus its support and its connections).

[0046] With reference to the drawings, the device comprises:

[0047] In FIG. 1, a reflecting screen 47, two centering screws 21.

[0048] In FIG. 2, a fuel inlet 1 with its various accessories, an air-liquid separator 2, a small-diameter injector tube 3, a cooling tube 4 with its axial abutment, a pressure gauge 5, a transparent tube 6, a filling cock 7, a valve coupling for setting level and for setting air pressure 8, the wall of the fireplace hood 9, a support 10 fixed on the hood by screws 11 and springs 12, a two-part holding and protection tube 13, a centering system 14, a centering system 15, a protective tube 16, a centering system 17, a protective tube 18 together with holding screws 19 therefor, two gaskets 29, two downwardly bent outlets 30.

[0049] In FIG. 3, on the left-hand side, an air-feed box, a hearth support 20, a fan 22, a deflector 23, a heat screen 24, support legs 5, a combustion pot 26 with its air injection holes at various levels, a receptacle 27, a horizontal stamped disk 28, disks of grid or expanded metal or perforated sheet metal 31 (with the number of these disks depending on the type of burner), a tube 32, a circular stamped support 33, peripheral spacers 34 on axes 35, vertical peripheral radial fins 36, a stamped ring 37, a transparent ceramic glass tube 38, two safety thermocouples 39, and in a variant, on the right-hand side of FIG. 3, supporting spacers 40, air injection rings 41 (the number of rings depending on the type of burner), transparent ceramic glass tubes 42 (the number of tubes being a function of the type of burner), a top fixing ring 43, fixing ties 44 with springs 45 and nuts 46, a centralizer 47 with rods 48.

[0050] In FIG. 4, a heat-recovery cooler 49 (minus its support and its couplings). 

1. A heating device suitable for fitting to a stove or to a closed woodburning fireplace to transform it into a liquid fuel fireplace, the device comprising: a combustion device comprising: a box containing a fan; at least one transparent ceramic glass tube, and a combustion pot, both placed on the box; and a liquid fuel feed device for feeding liquid fuel to the combustion device, the liquid fuel feed device comprising an injector tube situated inside a cooling tube.
 2. A device according to claim 1 , further comprising an air-fuel separator for ensuring a regular flow of liquid fuel by eliminating air bubbles.
 3. A device according to claim 1 , in which said injector tube has two small-diameter angled outlets enabling drops of liquid fuel to flow without dispersion.
 4. A device according to claim 1 , in which said injector tube is inclined and cooled by water contained and flowing in said cooling tube without a mechanical system for driving the water.
 5. A device according to claim 3 , further comprising a tube protecting the end of said injector tube and said two outlets to prevent them becoming clogged.
 6. A device according to claim 1 , further comprising a tube or a heat-recovering cooler preventing liquid fuel drops from igniting over a fraction of their fall in said combustion pot.
 7. A device according to claim 1 , in which said fan is a variable speed fan.
 8. A device according to claim 1 , in which said at least one ceramic glass tube is placed on said box and supports said combustion pot, making it possible to see the reddening thereof and the combustion through air injection holes provided in said combustion pot or in an air injection ring.
 9. A device according to claim 1 , further including fins for eliminating the turbulent effect of the injected air, thus providing better combustion.
 10. A device according to claim 1 , in which said combustion device further comprises a conically-shaped receptacle receiving drops of liquid fuel without any splashing, thereby contributing to keeping said combustion pot clean.
 11. A device according to claim 1 , in which said combustion device further includes a solid horizontal disk, horizontal disks in the form of grids or expanded metal or perforated sheet metal, a tube, and spacers which are disposed inside said combustion pot, facilitating combustion and creating a glowing embers effect.
 12. A liquid fuel burner suitable for fitting to a wood fireplace, the burner comprising: a liquid fuel combustion pot comprising a bottom wall; a first wall provided with holes for injecting air for combustion; a device for feeding liquid fuel to the combustion pot, said device comprising a double-walled tube to deliver a flow of liquid fuel and to cool it; and a device for delivering air to the air injection holes, which device comprises a box fitted with an air fan, air-guiding members, and a second wall extending outside said first wall.
 13. A burner according to claim 12 , in which an outside portion of said double-walled tube contains water, said double-walled tube being inclined and having a portion outside said fireplace so as to allow the liquid fuel to flow under gravity and so as to cool the liquid fuel by a flow of water contained inside the tube without requiring the water to be driven mechanically.
 14. A burner according to claim 12 , in which said second wall is transparent, so as to enable the reddening of the combustion pot to be seen.
 15. A burner according to claim 12 , in which said second wall is placed on said box and supports said combustion pot.
 16. A burner according to claim 12 , further including a heat screen protecting the air fan from heat due to radiation emitted by said combustion pot.
 17. A liquid fuel burner for a fireplace, the burner comprising: a combustion pot provided with injection holes for combustion air; an injector tube for bringing a liquid fuel to vertically above the combustion pot, and allowing fuel drops to drip from one end of the injector tube; a tube terminated by a vertical portion protecting the fuel after it leaves the injector tube; a tubular wall extending around said combustion pot; and a box containing a fan to deliver combustion air, and supporting said tubular wall and said combustion pot.
 18. A burner according to claim 17 , further comprising a cooling tube extending around said injector tube, with a first portion extending inside the fireplace and a second portion extending outside the fireplace, said cooling tube forming a leakproof radiator for cooling the injector tube by a heat-pipe effect.
 19. A burner according to claim 17 , further comprising a receptacle including a conical portion having a small angle at the apex and placed at the center of said combustion pot so as to receive said drops of fuel.
 20. A burner according to claim 17 , further comprising fins for eliminating turbulence due to said air fan, and also a heat screen for protecting the air fan. 